Partially restore small-T optimization for very small (empty) T.

This is particularly helpful for SkRecord::replace<NoOp>, which now doesn't go
off and allocate a pointless byte.

BUG=skia:2378
R=fmalita@chromium.org, bungeman@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/269543025

git-svn-id: http://skia.googlecode.com/svn/trunk@14622 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed